Excerpt: We've put close to 80+ burn in hours on these so far, and have seen a noticeable change in audio reference. I've read that a solid 300 hours is needed in order to get the true performance of these phones. When they were pulled out of the box they sounded quite muddled. The mids were very held back. Vocals were forward but not quite where they should have been. I've seen a lot about the lacking bass of the K 702 and found that out of the box the bass was "noticeable".
Pros: Comfortable, Compact, Durable, Forward Mids
Cons: 35mm Termination, Muddled Mids, No Bass Reference, Vocals Fall Off
Summary: For me these a double-edged sword. They are the first decent cans that I actually find comfy - having big jug-ears ! At 9.5cms in diameter, and perfectly round, they actually completely surround my ears, rather than touching them. Nice. But, the foam is very firm, so much so, that they feel more like soft polystyrene, as opposed to memory foam. These literally sit around your ears, as opposed to cushioning softly around them.
Summary: I used to own a pair of Sennheiser HD 650's purchased in March 2007 from an Amazon trader called Electromonster, for the amazing price of £169.00 (40% off at the time). I sold them in 2010 for more or less what I paid for them new, but I am staggered at the prices currently being charged. They were quite easy to live with, smooth, articulate, and comfortable.